Ernest van den Haag, a Professor of Jurisprudence at Fordham University who has studied the question of deterrence closely, wrote: "Even though statistical demonstrations are not conclusive, and perhaps cannot be, capital punishment is likely to deter more than other punishments because people fear death more than anything else. They fear most death deliberately inflicted by law and scheduled by the courts. Whatever people fear most is likely to deter most. Hence, the threat of the death penalty may deter some murderers who otherwise might not have been deterred. And surely the death penalty is the only penalty that could deter prisoners already serving a life sentence and tempted to kill a guard, or offenders about to be arrested and facing a life sentence. Perhaps they will not be deterred. But they would certainly not be deterred by anything else. We owe all the protection we can give to law enforcers exposed to special risks.